The present invention relates to the field of containers for bulk material. Particularly, the present invention relates to an improved and reusable drop box assembly or container for accepting, storing, stacking, transporting, and automatically discharging solid bulk material.
In the shipping and handling of solid bulk materials it has become the standard practice to use dispensing types of bins, called drop boxes, drop containers, or the like. These specialized containers permit less necessary handling and prevent the loss of contents due to spillage.
Many prior art containers exist to provide a bottom discharge for solid bulk materials. For example, U.S. Pat. No. 3,318,473 to Jones et al., U.S. Pat. No. 3,799,409 to Goerke, U.S. Pat. No. 4,210,273 to Hegele, and U.S. Pat. No. 5,441,321 to Karpisek teach use of containers which can be opened at the bottom side to discharge contents. Each of these devices requires some form of physical manipulation by an operator after the container has been positioned to discharge the subject material. The invention of the ""473 patent utilizes a slidable gate which is pulled to an open position to commence dispensing. The ""409 patent is very similar, requiring the operator to pull a sheet 32 to expose an opening. The ""273 patent teaches the use of release straps, which when pulled permit the bottom of the container to open completely. The invention of the ""321 patent uses latch means 50 to release a hinged door.
Other prior art devices teach mechanical manipulation of a chute or locking mechanism to permit the contents discharge. Such mechanical features are shown in U.S. Pat. No. 3,217,912 to McKeon, U.S. Pat. No. 3,797,878 to Fagre et al., U.S. Pat. No. 5,011,360 to Abram et al., U.S. Pat. No. 5,746,463 to Nagata, and U.S. Pat. No. 5,897,152 to Nagata. Such devices are complex, with many moving parts which may become jammed, damaged, or otherwise inoperable over time.
Still other devices, such as shown in U.S. Pat. No. 3,127,084 to Williams, have a single pair of simple hinged doors which swing open to discharge the contents of the container. However, because each of the doors is capable of a complete 90xc2x0 pivot, there is a great possibility for the contents to be spilled from the opening. International Publication No. WO 99/19219 of PCT/GB98/03028 shows a pallet base having downwardly opening doors of less than 90xc2x0. However, the invention disclosed is limited to a mechanical base and does not provide the numerous advantages of an integrated assembly as disclosed herein.
The present invention provides bins constructed to be light and compact so as to be capable of stacking and economically shipping. These bins also facilitate handling with a minimum of equipment and maneuvering, and are capable of automatically discharging the contents of the bin by gravity into a wide variety of receptacles, vehicles, and the like. Further, the bins are capable of compaction into a small, substantially flat unit when emptied for return shipping.
The present invention addresses these shortcomings of the prior art to provide a reusable, stackable container for storage, transportation, and discharge of a bulk material.
In accordance with the present invention, a new drop box container having a base frame, a pair of runners to elevate the base frame from a surface, a first pair of door panels attached along one edge to the base frame, a sleeve having a plurality of sidewalls, and a top frame is disclosed. The base frame is preferably designed with a plurality of side members configured to define an opening, and a channel seated within the side members and circumjacent the openingxe2x80x94an upper surface of each side member being sloped away from the channel and toward the opening. It is an aspect of the present invention to allow engagement of the container by a forklift or the like from four directions.
In a preferred embodiment of the present invention, it is an aspect to provide a first means for securing the sleeve within the channel of the base frame. The first means for securing may comprise a plurality of connecting members on one of either the base frame or the sleeve. Such connecting members include a plurality of male connecting members on the sleeve and a plurality of corresponding female connecting members on the base frame.
It is an aspect of the invention to provide a second means for securing the sleeve within the top frame. The second means for securing may comprise a plurality of connecting members on one of either the top frame or the sleeve. Such connecting members include a plurality of male connecting members on the sleeve and a plurality of corresponding female connecting members on the top frame.
It is another aspect of the invention to provide a modular drop box container having a sleeve with at least one integral side support. The at least one integral side support in one embodiment comprises a T-fold running from one outer edge to the other in at least one sleeve sidewall. Additionally, or alternatively, the at least one integral side support may comprise double-bend comers. The sleeve may also be configured to include a plurality of fold lines allowing the sleeve to be folded and stored within the base frame when compacted.
A further aspect of the invention provides an integral support along an edge of the first pair of door panels distal to the edge of attachment and below a plane defined by the first pair of door panels. The integral support preferably comprises a means for increasing the container volume by providing a cavity defined within the integral support and being open to the container interior.
In another aspect of the invention a second pair of door panels attached to the base frame is provided. The second pair of door panels preferably includes means for preventing the second pair of doors panels from binding with the first pair of door panels during closing.
The top frame of the present invention may comprise an opening defined in a surface of the frame to allow loading of bulk material directly into the assembled container. A detachable lid for covering the opening of the top frame may also be provided with an optional means for locking the lid to the top frame.
Preferably, the components of the present invention are molded from an injection mold material such as high density polyethylene (HDPE), polypropylene, ABS, polystyrene, high impact polystyrene, polyamides, and thermoplastic polyesters, with or without additives. For structural integrity, the plastic sheet material for the sleeve may be corrugated.
These and other aspects of the present invention set forth in the appended claims may be realized in accordance with the following disclosure with particular reference to the accompanying drawings.